To punch or not to punch, that is the question
When knuckles meet skull during a confrontation, the skull will always win. So, maybe the fist is not the best hand striking tool. The palm heel strike may be the better choice.
To execute a palm heel strike, the hand is pulled back as far as possible, locking the wrist, and the fingers curl slightly forward. The palm and finger tips should face the target. Contact is made with the very bottom of the palm just in front of the wrist. The palm heel strike is quite effective. If used on a slightly upward angle, it has a tremendous amount of leverage.
A punch to the head will usually only affect the area where the knuckles make contact. Palm heel strikes have a secondary effect. A palm strike to the head probably will not cause much damage to the contact point, but it will have an effect on the neck and usually will jolt the body. A palm heel strike the underside of the will often produce a knock-out due to the whip lash effect. A palm heel strike anywhere to the head area will almost always affect balance, because the it will take the assailant's ears out of line with the hips, which will expose other parts of the body to combinations or a takedown. The palm heel strike may be used effectively to the hard parts of the body. Punches are best used against the softer muscular parts of the body to avoid injury to the puncher. Palm heel strikes do not appear as violent as clenching your fist and striking someone. To a witness, an open hand strike may appear as a push.
The most common injury in punching occurs when the fist strikes with the last two knuckles. The 5th metacarpal (between the knuckles of the middle finger and pinkie) usually breaks, commonly referred to as a boxer's fracture, which is why boxers always tape their fists prior to training or fighting. A fracture will take 6-8 weeks to heal, while a sprain (tear in ligament) could take up to 6 months to heal, and then rehabilitation could take another 3-4 months.
Grip strength comes from the ulnar side (pinky side) of the hand. A boxer's fracture would significantly affect your grip. Try to hold anything with a handle without using your fourth finger. This means you will not be able to defend yourself by grabbing or gripping a weapon.
Another consideration is cutting the knuckles on the perpetrator's teeth. Punches are usually directed to the head area, but the mouth should be avoided. However, the teeth may be struck inadvertently. Humans have the very infectious mouths, including AIDS. Once you break skin you are introducing all those germs to your body. When you open your hand from a fist, the tendons pull back. If the knuckles are cut when a fist strikes teeth, the act of opening the hand pulls bacteria in. Serious infection can set in within 24-48 hours. When a mouth strike is made with the heel of the palm. any impact with the mouth distributes the contact area making it difficult to break skin if the teeth are struck. With a punch, one knuckle may hit the teeth, breaking skin easily, because the skin on the Dorsal side (top of the hand) is easily cut because it is very thin. The opposite is true of the skin on the palm. Germs do not fester as easily in the fleshy palm of the hand as they do in the knuckles. With a properly executed palm heel strike, the chances of injuring the hand are slim.